Washington Constitution Art. 23, § 2. Constitutional Conventions

Whenever two-thirds of the members elected to each branch of the legislature shall deem it necessary to call a convention to revise or amend this Constitution, they shall recommend to the electors to vote at the next general election, for or against a convention, and if a majority of all the electors voting at said election shall have voted for a convention, the legislature shall at the next session, provide by law for calling the same; and such convention shall consist of a number of members, not less than that of the most numerous branch of the legislature.